Practice question

The rescue effect and recolonization are related but distinct. Rescue occurs when immigrants enter a patch that is still occupied and prevent its local population from going extinct. Recolonization occurs after extinction, when dispersers establish a new population in an empty patch. Therefore, the wording “recolonization of a previously extinct patch” describes colonization following local extinction, not rescue in its strict ecological meaning. Movement of colonists is migration or dispersal, making that listed alternative closer to the mechanism, although “recolonization” itself would be the precise term if offered. This distinction matters in metapopulation models: rescue reduces the extinction probability of occupied patches, whereas recolonization increases the transition rate from empty to occupied. Both depend on landscape connectivity and sources of migrants. The preserved key conflates these processes and is scientifically inaccurate under standard definitions. A patch that has already lost every individual cannot be rescued from extinction; it can only be colonized again. Clear terminology helps separate persistence within patches from restoration of occupancy across the patch network.